This invention relates to electromechanical systems which require the conduction of electrical current through an anti-friction bearing operating in a vacuum environment. More particularly, this invention has particular advantage when incorporated into rotating anode x-ray tubes having ball bearings operating within races in the vacuum environment and which conduct the anode-cathode current of the tube.
Such systems have experienced limited life in the past, due in part to spark erosion of the bearings occasioned by random current interruption which has been observed to occur while the equipment is rotating. Although prior art systems, including x-ray tubes, have had opposing conductive surfaces which were relatively moveable, such prior art structures have been observed to have so little capacitance as to be ineffective to suppress arcing.